1. The Technical Field
The present invention relates to domestic containers for use in transportation of cargo on railroads, in particular the kind of domestic containers which may be transferred back and forth between truck trailers and railroad cars, and which, when particularly mounted on railroad cars, are stacked in tandem. The present invention, in particular, relates to support brackets for use in repairing and/or reinforcing such domestic containers which have composite material constructions of part metal, part wood or other material.
2. The Prior Art
In addition to dedicated boxcars, tank cars and flat cars, cargo may be transferred via the railroads, using devices which, in the U.S. at least, are commonly known as "domestic containers". Such containers typically have a generally rectangular cross-sectional configuration, and have a composite construction, in which a metal frame is provided, and wood or other materials are used for the panels which form the side, end, top and bottom walls of the container. Typically, the sides and top are steel or aluminum panels and the floor is wood. There is typically a wood liner for the sides. A typical domestic container may have a length of forty eight feet (lengths of 40 feet, 45 feet and 53 feet are also known), a height of nine and one-half feet, and a width of eight and one-half feet. Such a container may have an empty weight on the order of eight to nine thousand pounds, and may have a loaded weight of more than sixty five thousand pounds.
Such containers may be transported both on truck trailers, as well as on specially configured, low profile railroad cars. Typically, when used on such railroad cars, a first domestic container is placed into a well formed into the railroad car. A second domestic container is then stacked atop the first, for efficient loading and use of available space. Such containers are typically not owned by the railroads on which they are used. Instead, such containers are usually leased from other entities.
Manipulation of such domestic containers in a railyard is typically accomplished by cranes or self-propelled loaders which grasp the containers by inserting hooks into attachment apertures formed in metal "blocks" in the frame of each container. Typically, two such blocks are located at opposite sides of the container, at two locations, a short distance from each end of the container. For example, for the example mentioned above, two such attachment apertures may be positioned four feet or thereabout from each end of the container.
These blocks, in which the attachment apertures are located, typically project slightly upwardly and outwardly, relative to the adjacent wall panels of the container. As such, when one container is stacked above another, the weight of the upper container in large part is concentrated through the lower container frame, and in particular, the metal blocks having the attachment apertures. Accordingly, the metal structure of the frame making up and surrounding the blocks receives a disproportionate amount of stress and loading.
The metal of the frames of such domestic containers is typically iron or steel which may not be specially treated or formulated to resist attack from the elements, with the possible exception of a somewhat fragile coating of paint. The metal then, over prolonged exposure to the elements, is attacked by rust and weakened. Although the containers are made to be watertight, repeated pounding and stresses cause moisture leakage into the interior of the containers, along the seams between the frame and the wall panels, which causes the interior frame members to also be attacked by rust and/or other chemical corrosion, further weakening the structure of the container.
Eventually, the repeated pounding and stresses which such containers encounter, as they are transported, as well as during the railyard handling and stacking, awaiting transport, causes the frame structures of the containers to buckle and fail. Most often, this buckling takes place at one or more locations in the immediate vicinity of the blocks for the attachment apertures. Once this buckling has begun, it progresses quickly, and the container is soon rendered unusable, even though apart from the localized buckling, the rest of the container may be in generally good condition. Such containers have been in use for well over ten years, and the aforementioned buckling phenomenon has been known to occur after only a few years of use of any particular container. So far, an effective solution to restore such containers to utility, for more than a few months at a time, if at all, without totally reconstructing the container, is believed not to have been found, before the present invention.
Because each such container may cost up to twenty five thousand dollars or more to replace, the premature loss of function of each container creates a significant burden on the railroads, in terms of finding usable containers in order to maintain the flow of goods, but also in terms of the amount of money "tied up" in unusable capital. It is believed that at the present time, many thousands of such containers, representing millions of dollars of investment, are idled due to such damage.
Accordingly, it would be desirable to provide an apparatus and method for supporting the structures of such domestic containers, which will enable such containers to be restored to useable condition.
It would also be desirable to provide an apparatus and method for supporting the frame structures of such domestic containers, which may be applied to existing, still usable containers, in order to prevent such containers from becoming prematurely unusable.
Methods are known which have been used in an attempt to restore such containers to useful function. One method which is known is to force the collapsed frame structure, in the vicinity of the block, back into its original shape and then place several sheets or plates of metal around the interior surface of the metal block forming the support for the attachment aperture, like a form of flashing, which covers the area of the block and portions of the adjacent frame structure. Typically, these sheets or plates are all generally flat and are welded together, and to the original metal of the container frame, at the edges where these sheets or plates meet. As such, the flashing provides only limited support to the frame structure, and such repairs have been known to last only a short time before buckling sets in again. This may be due to the fact that the welds between adjacent sheets or plates are subjected to and must withstand considerable bending forces, which the joined, non-integrally formed flashing plates are ill-equipped to do.